High temperature coatings for a preclean and etch apparatus and related methods

ABSTRACT

A coating and a method to form the coating is proposed for a semiconductor film pre-clean and etch apparatus. The coating may be employed in environments where it is difficult to use a traditional coating or coating method. The coatings provide advantages including: an ability to effectively deliver hydrogen radicals and fluorine radicals to a wafer surface in one apparatus or individually in two apparatuses; a coverage of high aspect ratio features on critical components; an operability in high temperatures exceeding 150° C.; and a protection of a part with high aspect ratio features underneath the coating, thereby preventing metal and particles on a processed wafer.

FIELD OF INVENTION

The present disclosure generally relates to an apparatus for performinga pre-clean or an etch process on semiconductor wafers and relatedmethods. More particularly, the disclosure relates to coatings for partswithin the apparatus formed via an atomic layer deposition (ALD)process. The coatings provide advantages of being able to effectivelydeliver hydrogen radicals and fluorine radicals to a wafer surface inone apparatus or individually in two apparatuses formed by a remoteplasma unit, cover high aspect ratio features on critical components andoperate in a high temperature condition with metal-free andparticle-free performance.

BACKGROUND OF THE DISCLOSURE

Coatings have been employed on parts within semiconductor filmmanufacturing apparatuses in order to avoid particle generation thatcould adversely affect a film formed on a semiconductor wafer. Thesecoatings have been found in particular on apparatuses where pre-clean oretch processes may take place. The coatings may include metals andceramics, such as nickel, aluminum oxide, yttrium oxide, zirconiumoxide, magnesium oxide, or calcium oxide, for example. The pre-clean oretch processes may involve a chemistry or a plasma that may react withthe parts below the coatings. Thus, the coatings serve as a protectivebarrier for the parts.

However, there are some issues with these traditional coatings. First,hydrogen radicals show extremely fast recombination on some coatingssuch as nickel, which is commonly used as a protective barrier influorine radical environments. Carbon removal function cannot beachieved in this apparatus because of a limited amount of hydrogenradicals being delivered to a wafer.

Second, it is a big challenge for traditional coatings to accommodateboth oxide removal and carbon removal using reactive F and H in oneapparatus, respectively. Between one chemical process to the other,fluorine, hydrogen, and coating material may react and generateparticles. Seasoning steps or dummy wafers may be needed to contain thisproblem, but it leads to low throughput.

Third, certain coatings may not be able to withstand environments wherethe temperature exceeds 150° C. Many pre-clean/etch processes may exceedthe temperature of 150° C., so these coatings may prove to bedetrimental in use at those higher temperatures due to physical andchemical decomposition of the coatings during the processes. Forexample, plasma spray Y₂O₃ coating cracks upon heating to around 150°C., leading to particle generation. Aluminum metal issues show up onwafer with anodized, PEO and ALD Al₂O₃ coatings in the reactive fluorineand reactive hydrogen chemical environment above 150° C.

Fourth, there may be difficulty in applying a coating uniformly on partswith high aspect ratio features. For example, a coating applied via aplasma spray process may not be able to cover high aspect holes onshowerhead and gas distribution tunnels. The uncovered substrate mayresult in generation of particles that can adversely affect a filmformed on a semiconductor wafer.

As a result, an ex-situ or in-situ coating that is able to efficientlydeliver hydrogen radicals to wafers, while withstand higher temperaturesand harsh chemical environments is desired in apparatuses deliveringboth reactive fluorine and reactive hydrogen species. It is also desiredthat the coating be applied with a uniform thickness and not generatemetal/particles when subjected to the higher temperatures and harshchemical environments.

SUMMARY OF THE DISCLOSURE

This summary is provided to introduce a selection of concepts in asimplified form. These concepts are described in further detail in thedetailed description of example embodiments of the disclosure below.This summary is not intended to identify key features or essentialfeatures of the claimed subject matter, nor is it intended to be used tolimit the scope of the claimed subject matter.

In accordance with at least one embodiment, a semiconductor filmpre-clean/etch apparatus comprises: a reaction chamber; a wafer holderwithin the reaction chamber configured to hold a semiconductor wafer; agas transport path configured to ensure a gas delivery to the reactionchamber and a uniform mixture of at least two gases; a gas distributiondevice for dispersing a gas across the semiconductor wafer; a gasmanifold to help deliver hydrogen radical to wafer edge; a remote plasmaunit that converts a first gas provided by a first gas source into aradical gas; wherein at least one of the wafer holder, the reactionchamber, the gas transport path, the gas distribution device, the gasmanifold, or the remote plasma unit comprises a coating with a firstlayer and a second layer; wherein at least one of the first layer or thesecond layer of the coating is formed by atomic layer deposition (ALD);and wherein the first layer and the second layer comprise differentmaterials.

In accordance with at least one embodiment, a method for forming acoating for a semiconductor film pre-clean/etch apparatus comprises:preparing a first surface to be coated; cleaning the first surface;depositing a first coating layer on the first surface with an atomiclayer deposition (ALD) technique; depositing a second coating layer onthe first coating layer to form a multi-layer coating; repeating thestep of forming the first coating layer and forming the second coatinglayer as required; and performing a post-coating treatment on thecomposite coating; wherein the first coating layer comprises a materialdifferent from that of the second coating layer; wherein thesemiconductor film deposition apparatus comprises: a wafer holder; areaction chamber; a gas transport path, a gas distribution device; a gasmanifold; and a remote plasma unit; and wherein the composite coating isdisposed on at least one of: the wafer holder; the reaction chamber; thegas transport path, the gas distribution device; the gas manifold; orthe remote plasma unit.

BRIEF DESCRIPTION OF THE DRAWING FIGURES

These and other features, aspects, and advantages of the inventiondisclosed herein are described below with reference to the drawings ofcertain embodiments, which are intended to illustrate and not to limitthe invention.

FIG. 1 is a cross-sectional illustration of a semiconductor filmpre-clean apparatus with an ex-situ coating in accordance with at leastone embodiment of the invention.

FIG. 2 is a cross-sectional illustration of a semiconductor filmpre-clean apparatus with an in-situ coating in accordance with at leastone embodiment of the invention.

FIGS. 3A and 3B are cross-sectional illustrations of an example of partswith enclosure space, a remote plasma unit, in accordance with at leastone embodiment of the invention.

FIGS. 4A and 4B are cross-sectional illustrations of parts with highaspect ratio features, a gas distribution system or showerhead, inaccordance with at least one embodiment of the invention.

FIG. 5 is a cross-sectional illustration of a part with a coatingarrangement in accordance with at least one embodiment of the invention.

FIG. 6 is a cross-sectional illustration of a part with a coatingarrangement in accordance with at least one embodiment of the invention.

FIG. 7 is a cross-sectional illustration of a part with a coatingarrangement in accordance with at least one embodiment of the invention.

FIG. 8 is a flowchart illustrating a method of coating in accordancewith at least one embodiment of the invention.

It will be appreciated that elements in the figures are illustrated forsimplicity and clarity and have not necessarily been drawn to scale. Forexample, the dimensions of some of the elements in the figures may beexaggerated relative to other elements to help improve understanding ofillustrated embodiments of the present disclosure.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

Although certain embodiments and examples are disclosed below, it willbe understood by those in the art that the invention extends beyond thespecifically disclosed embodiments and/or uses of the invention andobvious modifications and equivalents thereof. Thus, it is intended thatthe scope of the invention disclosed should not be limited by theparticular disclosed embodiments described below.

The illustrations presented herein are not meant to be actual views ofany particular material, structure, or device, but are merely idealizedrepresentations that are used to describe embodiments of the disclosure.

As used herein, the term “atomic layer deposition” (ALD) may refer to avapor deposition process in which deposition cycles, preferably aplurality of consecutive deposition cycles, are conducted in a processchamber. Typically, during each cycle, the precursor is chemisorbed to adeposition surface (e.g., a substrate surface or a previously depositedunderlying surface such as material from a previous ALD cycle), forminga monolayer or sub-monolayer that does not readily react with additionalprecursor (i.e., a self-limiting reaction). Thereafter, if necessary, areactant (e.g., another precursor or reaction gas) may subsequently beintroduced into the process chamber for use in converting thechemisorbed precursor to the desired material on the deposition surface.Typically, this reactant is capable of further reaction with theprecursor. Further, purging steps may also be utilized during each cycleto remove excess precursor from the process chamber and/or remove excessreactant and/or reaction byproducts from the process chamber afterconversion of the chemisorbed precursor. Further, the term “atomic layerdeposition,” as used herein, is also meant to include processesdesignated by related terms such as, “chemical vapor atomic layerdeposition,” “atomic layer epitaxy” (ALE), molecular beam epitaxy (MBE),gas source MBE, or organometallic MBE, and chemical beam epitaxy whenperformed with alternating pulses of precursor composition(s), reactivegas, and purge (e.g., inert carrier) gas.

As used herein, the term “chemical vapor deposition” (CVD) may refer toany process wherein a substrate is exposed to one or more volatileprecursors, which may react and/or decompose on a substrate surface toproduce a desired deposition.

FIG. 1 illustrates a semiconductor film pre-clean apparatus 100 with anex-situ coating in accordance with at least one embodiment of theinvention. The semiconductor film pre-clean apparatus 100 comprises: areaction chamber housing 110; a wafer holder or susceptor 120,configured to hold a semiconductor wafer 130; a gas distribution systemor showerhead 140; a gas manifold 150; a gas transport path 160; aremote plasma unit 170; a first gas source 180; a second gas source190A; a third gas source 190B; and a fourth gas source 190C.

The remote plasma unit 170 converts a gas provided by the first gassource 180 into a radical gas. An example of a radical gas may include afluorine radical gas used to remove a film, such as silicon oxide (SiOx)or silicon germanium oxide (SiGeOx), from the semiconductor wafer 130.The second gas source 190A may provide a dilute gas or a reactant gaswith the gas from the first gas source 180 to the semiconductor wafer130 in order to remove a film, such as silicon oxide or silicongermanium oxide. The third gas source 190B may provide a gas activatedby remote plasma unit 170 to form a hydrogen radical gas during carbonremoval process. The fourth gas source 190C may provide an inert gas tohelp ignite remote plasma unit 170 and may also deliver radicals towafer 130. The gas transport path 160 ensures a uniform mixture of gasfrom the first gas source 180 and the second gas source 190A to bedelivered to the reaction chamber 110. The gas distribution system orshowerhead 140 distributes the gases evenly over the surface of thesemiconductor wafer 130. The gas manifold 150 may assist in efficientlydelivering a radical gas generated from the third gas source 190B towafer edge and improving carbon removal uniformity.

FIG. 2 illustrates a semiconductor film pre-clean apparatus 200 with anin-situ coating in accordance with embodiments of the invention. Thesemiconductor film pre-clean apparatus 200 comprises: a reaction chamberhousing 110; a wafer holder or susceptor 120, configured to hold asemiconductor wafer 130; a gas distribution system or showerhead 140; agas manifold 150; a gas transport path 160; a remote plasma unit 170; afirst gas source 180; a second gas source 190A; a third gas source 190B;a fourth gas source 190C; a plurality of precursor sources 195A-195D;and a fifth gas source 195E.

Similar to the ex-situ coating apparatus 100, the in-situ coatingapparatus 200 may also add precursor and purge gas sources to allow foran in-situ coating function. Taking the example of composite coating ordual-layer-coating with ALD-deposited alumina (Al₂O₃) and ALD-depositedyttrium oxide (Y₂O₃), the in-situ coating apparatus 200 may include atrimethylaluminum (TMA) source 195A and a water (H₂O) source 195B forin-situ ALD-deposited alumina coating. The in-situ coating apparatus 200may include an yttrium gas source 195C (such as Y(thd), CP₃Y, or(CpCH₃)₃Y, for example) and an oxygen gas source 195D (such as oxygen,ozone, a mixture of ozone and oxygen, or H₂O, for example) for in-situALD-deposited yttrium oxide (as described in U.S. Pat. No. 7,351,658,which is herein incorporated by reference). Moreover, a purge gas source195E may be connected from an upper stream of precursor gas sources(195A-195D) to remove excess precursors or precursor by-products afterconversion of a chemisorbed precursor.

Several types of part structures can be beneficial from the coatingmethod. One type of structures is parts with enclosure space, such as aremote plasma unit, where the radical gas is initially generated. Remoteplasma units may require a coating, because of the plasma bombardmentand corrosive chemical environment. However, common coating methodseither show problems or are not feasible. For example, particlesgenerated on common RPU coatings, such as anodize and PEO, can transitbetween carbon removal and oxide removal processes. Plasma spray cannotcoat due to the enclosed space and a small gas inlet/outlet. FIGS. 3Aand 3B illustrates a representative remote plasma unit 300. The remoteplasma unit 300 comprises a main body 310, a gas inlet 320, an RFgenerator 330, a gas outlet 340, and a coating 350. The coating 350covers the internal walls of the main body 310. Other portions of theremote plasma unit 300 may be covered by the coating 350. The coating350 may comprise ceramic coatings, such as aluminum oxide (Al₂O₃),yttrium oxide (Y₂O₃), yttrium fluoride (YF₃), yttrium oxyfluoride(YO_(x)F_(y)), aluminum fluoride (AlF₃), scandium oxide (Sc₂O₃), hafniumoxide (HfO₂), lanthanum oxide (La₂O₃), samarium oxide (Sm₂O₃),gadolinium oxide (Gd₂O₃), erbium oxide (Er₂O₃), zirconium oxide (ZrO₂),cerium oxide (CeO₂), or any combination of the above.

The gas distribution system or showerhead 140, gas delivery path 135,and gas manifold 190 are parts that may also be coated, as such partsare exposed to the radical gas generated by the remote plasma unit 160.FIG. 4A illustrates another type of parts with high aspect ratio holessuch as the gas distribution system or showerhead 140 in accordance withat least one embodiment of the invention. The gas distribution system orshowerhead 140 comprises a showerhead body 410 and a plurality of holes420. Gas flows through the plurality of holes 420 onto the semiconductorwafer 130. The plurality of holes 420 may comprise features with highaspect ratios and may also comprise different shapes, such as bevels andcurves. The features may provide large area surfaces on which particlescan be generated from the bulk of the showerhead body 410.

FIG. 4B illustrates the gas distribution system or showerhead 140 thatincorporates a coating to prevent the formation of particles. Aplurality of coatings 430 are applied to the plurality of holes 420. Theplurality of coatings 430 may comprise ceramic coatings, such asaluminum oxide (Al₂O₃), yttrium oxide (Y₂O₃), yttrium oxyfluoride(YO_(x)F_(y)), yttrium fluoride (YF₃), aluminum fluoride (AlF₃),scandium oxide (Sc₂O₃), hafnium oxide (HfO₂), lanthanum oxide (La₂O₃),samarium oxide (Sm₂O₃), gadolinium oxide (Gd₂O₃), erbium oxide (Er₂O₃),zirconium oxide (ZrO₂), cerium oxide (CeO₂), or any combination of theabove. The plurality of coatings 430 may also cover other portions ofthe showerhead body 410. While FIGS. 4A and 4B illustrate one geometryfor coatings of the parts, there may be more complex internal structuresto which the coatings may also apply. This may include the gas transportpath 135 and the gas manifold 150, which may have holes and bends withinthe geometry.

The coatings of the parts may preferably be composite coatings. FIG. 5illustrates one coating arrangement 500. The coating arrangement 500includes a part 510 that is to be coated. The part 510 may be made of amaterial comprising at least one of: aluminum alloys, cast iron,stainless steel, Hastelloy, Inconel, nickel alloy, ceramics, ceramiccoatings, or metal coatings. The part 510 is coated with a layer of afirst coating 520, followed by a layer of a second coating 530, andrepeated with a layer of the first coating 520 and a layer of the secondcoating 530. At least one or both of the first coating 520 or the secondcoating 530 may be applied via atomic layer deposition (ALD) techniques.The benefit of using an ALD technique includes the formation of a fullydense coat, while generating an isotropic microstructure. In cases whereonly one coating is done by ALD, the other coating may be done byanodization, chemical vapor deposition (CVD), plasma vapor deposition(PVD), plasma spray coating, or plasma electrolytic oxidation (PEO). Therepeating of the layers may be done as desired or needed.

The first coating 520 may comprise one of: aluminum oxide (Al₂O₃),yttrium oxide (Y₂O₃), yttrium fluoride (YF₃), yttrium oxyfluoride(YO_(x)F_(y)), aluminum fluoride (AlF₃), scandium oxide (Sc₂O₃), hafniumoxide (HfO₂), lanthanum oxide (La₂O₃), samarium oxide (Sm₂O₃),gadolinium oxide (Gd₂O₃), erbium oxide (Er₂O₃), zirconium oxide (ZrO₂),or cerium oxide (CeO₂). The second coating 530 may comprise one of:aluminum oxide (Al₂O₃), yttrium oxide (Y₂O₃), yttrium fluoride (YF₃),yttrium oxyfluoride (YO_(x)F_(y)), aluminum fluoride (AlF₃), scandiumoxide (Sc₂O₃), hafnium oxide (HfO₂), lanthanum oxide (La₂O₃), samariumoxide (Sm₂O₃), gadolinium oxide (Gd₂O₃), erbium oxide (Er₂O₃), zirconiumoxide (ZrO₂), or cerium oxide (CeO₂). The first coating 420 and thesecond coating 530 ideally do not comprise the same materials.

FIG. 6 illustrates a coating arrangement 600 in accordance with at leastone embodiment of the invention. The coating arrangement 600 includes apart 610 that is to be coated. The part 610 may be made of a materialcomprising at least one of: aluminum alloys, cast iron, stainless steel,Hastelloy, Inconel, nickel alloy, ceramics, ceramic coatings, or metalcoatings. The part 610 is coated with a layer of a first coating 620,followed by a layer of a second coating 630. At least one or both of thefirst coating 620 or the second coating 630 may be applied via atomiclayer deposition (ALD) techniques. In cases where only one coating isdone by ALD, the other coating may be done by anodization, chemicalvapor deposition (CVD), plasma vapor deposition (PVD), plasma spraycoating, or plasma electrolytic oxidation (PEO). The coating can beextended to more than two layers of different ALD coatings (such asyttrium oxide and aluminum oxide, for example) or may comprise only onelayer of coating (such as yttrium oxide for example). The repetition ofthe layers may be done as desired or needed.

The first coating 620 may comprise one of: aluminum oxide (Al₂O₃),yttrium oxide (Y₂O₃), yttrium fluoride (YF₃), yttrium oxyfluoride(YO_(x)F_(y)), aluminum fluoride (AlF₃), scandium oxide (Sc₂O₃), hafniumoxide (HfO₂), lanthanum oxide (La₂O₃), samarium oxide (Sm₂O₃),gadolinium oxide (Gd₂O₃), erbium oxide (Er₂O₃), zirconium oxide (ZrO₂),or cerium oxide (CeO₂). The second coating 630 may comprise one of:aluminum oxide (Al₂O₃), yttrium oxide (Y₂O₃), yttrium oxyfluoride(YO_(x)F_(y)), yttrium fluoride (YF₃), aluminum fluoride (AlF₃),scandium oxide (Sc₂O₃), hafnium oxide (HfO₂), lanthanum oxide (La₂O₃),samarium oxide (Sm₂O₃), gadolinium oxide (Gd₂O₃), erbium oxide (Er₂O₃),zirconium oxide (ZrO₂), or cerium oxide (CeO₂). The first coating 620and the second coating 630 ideally do not comprise the same materials.

FIG. 7 illustrates a coating arrangement 700 in accordance with at leastone embodiment of the invention. The coating arrangement 700 includes apart 710 that is to be coated. The part 710 may be made of a materialcomprising at least one of: aluminum alloys, cast iron, stainless steel,Hastelloy, Inconel, nickel alloy, ceramics, ceramic coatings, or metalcoatings. The part 710 is coated with a layer of a first coating 720,followed by a layer of a second coating 730 and a layer of a thirdcoating 740. At least one or all of the first coating 720, the secondcoating 730, and the third coating 740 may be applied via atomic layerdeposition (ALD) techniques. In cases where only one coating is done byALD, the other coating may be done by anodization, chemical vapordeposition (CVD), plasma vapor deposition (PVD), plasma spray coating,or plasma electrolytic oxidation (PEO). The coating can be extended tomore than two layers of different ALD coatings or may comprise only onelayer of coating. The repetition of the layers may be done as needed.

The first coating 720 may comprise one of: aluminum oxide (Al₂O₃),yttrium oxide (Y₂O₃), yttrium fluoride (YF₃), yttrium oxyfluoride(YO_(x)F_(y)), aluminum fluoride (AlF₃), scandium oxide (Sc₂O₃), hafniumoxide (HfO₂), lanthanum oxide (La₂O₃), samarium oxide (Sm₂O₃),gadolinium oxide (Gd₂O₃), erbium oxide (Er₂O₃), zirconium oxide (ZrO₂),or cerium oxide (CeO₂). The second coating 730 may comprise one of:aluminum oxide (Al₂O₃), yttrium oxide (Y₂O₃), yttrium oxyfluoride(YO_(x)F_(y)), yttrium fluoride (YF₃), aluminum fluoride (AlF₃),scandium oxide (Sc₂O₃), hafnium oxide (HfO₂), lanthanum oxide (La₂O₃),samarium oxide (Sm₂O₃), gadolinium oxide (Gd₂O₃), erbium oxide (Er₂O₃),zirconium oxide (ZrO₂), or cerium oxide (CeO₂). The third coating 740may comprise one of: aluminum oxide (Al₂O₃), yttrium oxide (Y₂O₃),yttrium oxyfluoride (YO_(x)F_(y)), yttrium fluoride (YF₃), aluminumfluoride (AlF₃), scandium oxide (Sc₂O₃), hafnium oxide (HfO₂), lanthanumoxide (La₂O₃), samarium oxide (Sm₂O₃), gadolinium oxide (Gd₂O₃), erbiumoxide (Er₂O₃), zirconium oxide (ZrO₂), or cerium oxide (CeO₂). The firstcoating 720, the second coating 730, and the third coating 740 ideallydo not comprise the same materials, such as yttrium oxide, hafniumoxide, and aluminum oxide.

Coating of the parts may require several steps. FIG. 8 illustrates amethod 800 for performing the coating. The method 800 comprises: asurface preparation step 810; a cleaning step 820; a coating step 830;and a post-coating treatment step 840. The substrate preparation step810 may include steps to ensure an optimized coating, including removingsharp edges that could cause stress on the coating, tighteningtolerances on gaps, and optimizing small hole design in order to reducelocalized non-uniform coating defects or Newton's rings caused bytrapped precursors during ALD coating. To increase coating adhesion andensure good coating quality, parts may be treated by texturing,polishing, and/or electropolishing.

The cleaning step 820 may depend on the part being coated. The cleaningstep 820 may remove surface carbon, particles, and excess metal from thepart. The cleaning step 820 may include alkaline, acid,electro-cleaning, and/or ozone treatment steps among others. Byperforming the cleaning step 820, uniformity and surface coverage of thecoating may be optimized.

The coating step 830 may comprise forming at least one coating layer byan ALD technique. The ALD technique may be done by in-situ or ex-situmethods. An exemplary method may be to form a first layer of aluminumoxide and a second layer of yttrium oxide via an ALD process (asdescribed in U.S. Pat. No. 7,351,658, which is herein incorporated byreference). The thickness of the aluminum oxide on a gas distributiondevice or showerhead may range between: 1-10,000 nm; 10-2,500 nm; or100-500 nm. If yttrium oxide is deposited as a coating for a gasdistribution device or showerhead, the thickness of yttrium oxide mayrange between: 1-10,000 nm; 10-2,500 nm; or 100-500 nm. The thickness ofthe aluminum oxide on a remote plasma unit may range between: 1-50,000nm; 10-25,000 nm; or 100-10,000 nm. If yttrium oxide is deposited on aremote plasma unit, the thickness of yttrium oxide may range between:1-50,000 nm; 10-25,000 nm; or 100-10,000 nm.

A coating formed in the manner described above may be used reliably forprocesses running at temperatures above 150° C. In addition, thealuminum oxide layer may achieve better interfacial coating quality onthe part to be coated in comparison to the yttrium oxide. The aluminumoxide layer then may reduce the stress in the yttrium oxide layer fromthermal expansion, thereby reducing the potential for cracking in theyttrium oxide. The aluminum oxide layer may also be efficient atimpeding migration of metals to the surface, such as magnesium andsodium.

The post-coating treatment step 840 may comprise improving the qualityor properties of the coating. Examples may include fluorinating orchlorinating the surface of the coating to better accommodateenvironments that have fluorine or chlorine. In addition, thepost-coating treatment step 840 may involve annealing the surface toremove internal stress and defects. Furthermore, by heating up to acertain temperature, binary or ternary ceramics can be achieved. Forexample, a composite coating of Al₂O₃ and Y₂O₃ can transform to yttriumaluminum garnet (YAG) or yttrium aluminum monoclinic (YAM) after hightemperature treatment with a specific ratio of Al₂O₃ and Y₂O₃.

The particular implementations shown and described are illustrative ofthe invention and its best mode and are not intended to otherwise limitthe scope of the aspects and implementations in any way. Indeed, for thesake of brevity, conventional manufacturing, connection, preparation,and other functional aspects of the system may not be described indetail. Furthermore, the connecting lines shown in the various figuresare intended to represent exemplary functional relationships and/orphysical couplings between the various elements. Many alternative oradditional functional relationship or physical connections may bepresent in the practical system, and/or may be absent in someembodiments.

It is to be understood that the configurations and/or approachesdescribed herein are exemplary in nature, and that these specificembodiments or examples are not to be considered in a limiting sense,because numerous variations are possible. The specific routines ormethods described herein may represent one or more of any number ofprocessing strategies. Thus, the various acts illustrated may beperformed in the sequence illustrated, in other sequences, or omitted insome cases.

The subject matter of the present disclosure includes all novel andnonobvious combinations and subcombinations of the various processes,systems, and configurations, and other features, functions, acts, and/orproperties disclosed herein, as well as any and all equivalents thereof.

1. A semiconductor film pre-clean/etch apparatus comprising: a reactionchamber; a wafer holder within the reaction chamber configured to hold asemiconductor wafer; a gas transport path configured to ensure a gasdelivery to the reaction chamber and a uniform mixture of at least twogases; a gas distribution device for dispersing a gas across thesemiconductor wafer; a gas manifold to helps deliver hydrogen radical towafer edge; and a remote plasma unit that converts a first gas providedby a first gas source into a radical gas; wherein at least one of thewafer holder, the reaction chamber, the gas transport path, the gasdistribution device, the gas manifold, or the remote plasma unitcomprises a coating with a first layer and a second layer; wherein atleast one of the first layer or the second layer of the coating isformed by atomic layer deposition (ALD); and wherein the first layer andthe second layer comprise different materials.
 2. The apparatus of claim1, wherein the first layer is on the gas distribution device and athickness of the first layer ranges between: 1-10,000 nm; 10-2,500 nm;or 100-500 nm.
 3. The apparatus of claim 1, wherein the second layer ison the gas distribution device and a thickness of the second layerranges between: 1-10,000 nm; 10-2,500 nm; or 100-500 nm.
 4. Theapparatus of claim 1, wherein the first layer is on the remote plasmaunit and a thickness of the first layer ranges between: 1-50,000 nm;10-25,000 nm; or 100-10,000 nm.
 5. The apparatus of claim 1, wherein thesecond layer is on the remote plasma unit and a thickness of the secondlayer ranges between: 1-50,000 nm; 10-25,000 nm; or 100-10,000 nm. 6.The apparatus of claim 1, wherein the first layer comprises at least oneof: aluminum oxide (Al₂O₃), yttrium oxide (Y₂O₃), yttrium fluoride(YF₃), yttrium oxyfluoride (YO_(x)F_(y)), aluminum fluoride (AlF₃),scandium oxide (Sc₂O₃), hafnium oxide (HfO₂), lanthanum oxide (La₂O₃),samarium oxide (Sm₂O₃), gadolinium oxide (Gd₂O₃), erbium oxide (Er₂O₃),zirconium oxide (ZrO₂), or cerium oxide (CeO₂).
 7. The apparatus ofclaim 1, wherein the second layer comprises at least one of: aluminumoxide (Al₂O₃), yttrium oxide (Y₂O₃), yttrium fluoride (YF₃), yttriumoxyfluoride (YO_(x)F_(y)), aluminum fluoride (AlF₃), scandium oxide(Sc₂O₃), hafnium oxide (HfO₂), lanthanum oxide (La₂O₃), samarium oxide(Sm₂O₃), gadolinium oxide (Gd₂O₃), erbium oxide (Er₂O₃), zirconium oxide(ZrO₂), or cerium oxide (CeO₂).
 8. The apparatus of claim 1, whereinboth the first layer and the second layer are formed by ALD.
 9. Theapparatus of claim 1, wherein the first layer is formed by ALD and thesecond layer is formed by at least one of: anodization, chemical vapordeposition (CVD), plasma vapor deposition (PVD), plasma spray coating,or plasma electrolytic oxidation (PEO).
 10. The apparatus of claim 1,wherein the first layer and the second layer form a composite coating onat least one of: the wafer holder, the reaction chamber, the gastransport path, the gas distribution device, the gas manifold, or theremote plasma unit.
 11. The apparatus of claim 10, wherein formation ofthe composite coating is repeated several times on at least one of: thewafer holder, the reaction chamber, the gas transport path, the gasdistribution device, the gas manifold, or the remote plasma unit.
 12. Amethod for forming a coating for a semiconductor film pre-clean/etchapparatus comprising: preparing a first surface to be coated; cleaningthe first surface; depositing a first coating layer on the first surfacewith an atomic layer deposition (ALD) technique; depositing a secondcoating layer on the first coating layer to form a multi-layer coating;repeating the step of forming the first coating layer and forming thesecond coating layer as required; and performing a post-coatingtreatment on the composite coating; wherein the first coating layercomprises a material different from that of the second coating layer;wherein the semiconductor film deposition apparatus comprises: a waferholder; a reaction chamber; a gas transport path, a gas distributiondevice; a gas manifold; and a remote plasma unit; and wherein thecomposite coating is disposed on at least one of: the wafer holder; thereaction chamber; the gas transport path, the gas distribution device;the gas manifold; or the remote plasma unit.
 13. The method of claim 12,wherein depositing the second layer is performed by at least one of:anodization, chemical vapor deposition (CVD), plasma vapor deposition(PVD), plasma spray coating, or plasma electrolytic oxidation (PEO). 14.The method of claim 12, wherein the first coating layer comprises atleast one of: aluminum oxide (Al₂O₃), yttrium oxide (Y₂O₃), yttriumfluoride (YF₃), yttrium oxyfluoride (YO_(x)F_(y)), aluminum fluoride(AlF₃), scandium oxide (Sc₂O₃), hafnium oxide (HfO₂), lanthanum oxide(La₂O₃), samarium oxide (Sm₂O₃), gadolinium oxide (Gd₂O₃), erbium oxide(Er₂O₃), zirconium oxide (ZrO₂), or cerium oxide (CeO₂).
 15. The methodof claim 12, wherein the second coating layer comprises at least one of:aluminum oxide (Al₂O₃), yttrium oxide (Y₂O₃), yttrium fluoride (YF₃),yttrium oxyfluoride (YO_(x)F_(y)), aluminum fluoride (AlF₃), scandiumoxide (Sc₂O₃), hafnium oxide (HfO₂), lanthanum oxide (La₂O₃), samariumoxide (Sm₂O₃), gadolinium oxide (Gd₂O₃), erbium oxide (Er₂O₃), zirconiumoxide (ZrO₂), or cerium oxide (CeO₂).
 16. The method of claim 12,wherein the first coating layer is on the gas distribution device and athickness of the first coating layer ranges between: 1-10,000 nm;10-2,500 nm; or 100-500 nm.
 17. The method of claim 12, wherein thesecond coating layer is on the gas distribution device and a thicknessof the second coating layer ranges between: 1-10,000 nm; 10-2,500 nm; or100-500 nm.
 18. The method of claim 12, wherein the first coating layeris on the remote plasma unit and a thickness of the first coating layerranges between: 1-50,000 nm; 10-25,000 nm; or 100-10,000 nm.
 19. Themethod of claim 12, wherein the second coating layer is on the remoteplasma unit and a thickness of the second coating layer ranges between:1-50,000 nm; 10-25,000 nm; or 100-10,000 nm.